[x3d-public] No Transform/Group/Shape inside HAnimJoint?

[Don Brutzman]

Joe, let's refer back to the specification.  John helpfully colorized an
excerpt earlier; let's review how the spec works.  Quote:

HAnimJoint : X3DGroupingNode {
> MFNode [in] addChildren [HAnimJoint,HAnimSegment]
> MFNode [in] removeChildren [HAnimJoint,HAnimSegment]
> SFVec3f [in,out] center 0 0 0 (-∞,∞)`
> MFNode [in,out] children [] [HAnimJoint,HAnimSegment]


This means that a HAnimJoint is itself an X3DGrouping node, but the
limitation brackets mean that the *children* field can only contain an
HAnimSegment or another HAnimJoint.  Thus HAnimJoint cannot contain
HAnimDisplacer.

Paddling upstream to look at the HAnim 2 definitions, that looks to be
consistent with the Joint definition: no Displacer node seen there.

   -
   https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19774/ISO-IEC19774-1/ISO-IEC19774-1v2.1/ISO-IEC19774-1v2.1-WD/Architecture/concepts.html#JointObject

So the two specifications (HAnim primary, X3D secondary, both
authoritative) look consistent to me.

Important: please check that logic in the specification prose sections
yourselves.

Therefore HAnimJoint should have no other children besides HAnimSegment
and/or another HAnimJoint.  Joe, that does not match your list of
acceptable children... we have to be really careful about these things.

btw thanks John for noting that X3DJSail documentation shows it is
inconsistent with that restriction.  I'll work on that sometime in the
future.

p.s. I think our prior SourceForge tickets have gotten scrambled on this
topic, we probably need to start a separate one.

all the best, Don

On Fri, Sep 12, 2025 at 3:31 AM Joe D Williams <joedwil at earthlink.net>
wrote:

> > HAnimJoint.
>
> The acceptable children for Joint in Basic skeleton are
> Displacer (for Segment geometry), Joint, Segment.
> Segment children=any x3d and Site .
> Site children=any x3d.
>
>
>
>
>
>
> -----Original Message-----
> From: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org
> ></x3d-public at web3d.org>
> Sent: Sep 9, 2025 3:50 AM
> To: John Carlson <yottzumm at gmail.com></yottzumm at gmail.com>
> Cc: Don Brutzman <don.brutzman at gmail.com>, <hanim at web3d.org>, Extensible
> 3D (X3D) Graphics public discussion <x3d-public at web3d.org></
> x3d-public at web3d.org></hanim at web3d.org></don.brutzman at gmail.com>
> Subject: Re: [x3d-public] No Transform/Group/Shape inside HAnimJoint?
>
> Hi John. Option 3 please. Recommend fixing the example models, not
> deleting the example models. The X3D specification implementation of the
> HAnim specification, both of which are authoritative, clearly shows that
> Transform/Group/Shape child nodes belong under HAnimSegment, not under
> HAnimJoint. * 26.3.5 HAnimSegment*
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/hanim.html#HAnimSegment
>
> No doubt the errors you have reported here are already detected and
> reported repeatedly by X3D XML Schema,X3D DOCTYPE, and X3D Schematron.
> Periodic unit testing logs capture such errors, X3D-Edit can check
> validation comprehensively as well Proper validation and correction of
> models prevents Garbage In Garbage Out (GIGO) syndrome.
>
> Incidentally, a large number of people have worked long + hard for years
> to implement both specifications. There is no need to worry about
> “fixing” the authoritative HAnim and X3D specifications unless
> you have a valid example demonstrating why such a change is needed. Have
> fun with valid X3D models! 🥸👌 all the best, Don
> --
> Don Brutzman
> X3D graphics, virtual worlds, Navy robotics
> https://faculty.nps.edu/brutzman
> On Mon, Sep 8, 2025 at 8:36 PM John Carlson via x3d-public <
> x3d-public at web3d.org (mailto:x3d-public at web3d.org)=""> wrote:I suggest we
> either deep six examples with Transform/Group/Shape children of HAnimJoint,
> or fix the standard. Here's the standard I am referring to: HAnimJoint :
> X3DGroupingNode { MFNode [in] addChildren [HAnimJoint,HAnimSegment] MFNode
> [in] removeChildren [HAnimJoint,HAnimSegment] SFVec3f [in,out] center 0 0 0
> (-∞,∞)` MFNode [in,out] children [] [HAnimJoint,HAnimSegment]
> SFString [in,out] description "" MFNode [in,out] displacers []
> [HAnimDisplacer] SFBool [in,out] bboxDisplay FALSE SFRotation [in,out]
> limitOrientation 0 0 1 0 [-1,1] or (-∞,∞) MFFloat [in,out]
> llimit [0 0 0] (-∞,∞) SFNode [in,out] metadata NULL
> [X3DMetadataObject] SFString [in,out] name "" SFRotation [in,out] rotation
> 0 0 1 0 [-1,1] or (-∞,∞) SFVec3f [in,out] scale 1 1 1
> (0,∞) SFRotation [in,out] scaleOrientation 0 0 1 0 [-1,1] or
> (-∞,∞) MFInt32 [in,out] skinCoordIndex [] [0,∞) MFFloat
> [in,out] skinCoordWeight [] [0,1] MFFloat [in,out] stiffness [0 0 0] [0,1]
> SFVec3f [in,out] translation 0 0 0 (-∞,∞) MFFloat [in,out]
> ulimit [0 0 0] (-∞,∞) SFBool [in,out] visible TRUE SFVec3f []
> bboxCenter 0 0 0 (-∞,∞) SFVec3f [] bboxSize -1 -1 -1
> [0,∞) or −1 −1 −1}See examples in the archive,
> e.g.:Humanoid Animation X3D Examples Archive, Winter And Spring, Lily
> Animated ()Humanoid Animation X3D Examples Archive, Winter And Spring, Leif
> Animated (
> https://www.web3d.org/x3d/content/examples/HumanoidAnimation/WinterAndSpring/LeifAnimatedIndex.html
> (
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/hanim.html#HAnimJoint))Humanoid
> Animation X3D Examples Archive, Winter And Spring, Tufani Animated ()If
> HAnimJoint IS a X3DGroupingNode, then X3DChildNodes should be acceptable.
> Is that how to read the standard?
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/grouping.html#X3DGroupingNode10.3.2
> (
> https://www.web3d.org/x3d/content/examples/HumanoidAnimation/WinterAndSpring/TufaniAnimatedIndex.html)
> X3DGroupingNodeX3DGroupingNode : X3DChildNode, X3DBoundedObject { MFNode
> [in] addChildren [X3DChildNode] MFNode [in] removeChildren [X3DChildNode]
> MFNode [in,out] children [] [X3DChildNode] SFBool [in,out] bboxDisplay
> FALSE SFNode [in,out] metadata NULL [X3DMetadataObject] SFBool [in,out]
> visible TRUE SFVec3f [] bboxCenter 0 0 0 (-∞,∞) SFVec3f []
> bboxSize -1 -1 -1 [0,∞) or −1 −1 −1}Anyway, that
> seems *REALLY* confusing! Any clarification on "overloading" of fields
> welcome! Thanks, John_______________________________________________</
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